Process useful in blind flight training



June 29, 1943. 4 w. c. OCKER 2,

- PROCESS USEFUL IN BLIND FLIGHT TRAINING Original Filed July 18, 1951 2Sheets-Sheet 1 llllillllllmullly I v Null Ill/l/nm MAL/4M C June 29,1943. w. c. OCKER 2,322,770

V PROCESS USEFUL IN BLIND FLIGHT TRAINING 7 Original Filegl July 18,1931 2 SheetkShaet 2 I- Array E I PatentedJune 29; 1943 I William C.Ocker, San Antonio, Tex, assignor to the Government of the United Statesas represented by the Secretary War Original application 111 18, 1931,Serial No. 551,606. Divided and this application October 7, 1933, SerialNo. 692,595

2 Claims. (01. 35-12) (Granted under the act of March 8 1883, as

amended April 80,- 1928; 370 0. G. 757) This invention described hereinmay be manufactured and used by or for the Government for.

governmental purposes, without the payment to me'of any royalty thereon.

This invention relates to a processuseful in training airplane pilots inthe art of blind flying, by which is meant flying without a naturalhorizon for guidance, as occurs in fogs, clouds and thick weather, andan object of the invention is to train a pilot to fly by, and placeabsolute reliance in, the artificial horizon established by his flyinginstruments. even though such instruments read contrary to th pilot'sown sensations.

This invention provides for the practical application under actualflying conditions .of the ideas and principles embodied in the trainingdevice patented by me May 8,1929, U. 8. Patent No. 1,715,304, by meansof which it was first successfully and forcibly demonstrated that,contrary to the then accepted theory of flight in- As a result of earlytraining methods, most pilots have felt that the flying sense waslargely one of muscular balance and that visual reference played a moreor less--insi niflcant part. The aviator lays great stress on thisspecial sense and the "feel of the ship" is usually considered the mostimportant attainment gained from experience. Hence, flying byinstruments was frowned upon by most of the early aviators and,

there is a general feeling among present day pilots that use-ofinstruments is in itself evidence oflack of the so-called "feel of theship and a deflciency of natural'flying ability. Ac-

cordingly, it has become a usual practice for an struction, thedependence by a pilot-without a natural horizon-on his. senses ratherthan his flight instruments will only lead him into error as to hisattitude and into disadvantageous maneuvers.

Further objects and advantages of the lnvention will become apparentfrom the following description, and from the accompanying drawings,wherein:

Fig. 1' is a view of an open-cockpit type of training plane equipped forinstruction in blind flying in accordance with the principles of theinvention; I

Fig. 2 is a view of a cabin plane reconstructed for blind flyinginstruction;

Fig. 3 is a vertical cross section of th covered compartment or cockpitfor the student pilot;

Figs. 4 and 5 are diagrammatic views illustrating the necessity fortraining even experienced pilots in the art of blind flying.

As a general rule, the experienced pilot avoids fog or clouds ratherthan chance the hazards of blind flying and when caught endeavors toescape as rapidly as possible. During war times and at present withcommercial aviation, it is not always possible to choose ideal weatherconditions, nor is it possible to have continued good weather on longflights. In the past, when flying was unusual, many crashes resultedfrom pilots being caught in fog. Today, with instruments, crashes due toweather, especially fog, are fewer but with a better understanding ofinstrument flying, such as the present invention gives, crashes fromfog, due to loss of flying sense" will be eliminated.

aviator, when flying without outside visual reference, to ignore theinstruments and to control theairplane in response to his own sense offeel or balance on the generally accepted theory that ones own senses ofequilibrium and orientation could always be depended on to furnishinforma tion as to the attitude of the airplane in the air in relation'to the earth.

Th fact that flying without a visual reference is unsafe has beenemphasized by crashes of air mail planes and of commercial air-transportplanes which endeavor to fly regardless of weather conditions. That onesown senses are far from infallible in maintaining equilibrium of theairplane in the air is also evidenced by the fact that many experiencedpilots have come out of a fog to flnd themselves off the course with awing down or even in inverted flying position. A very large proportionof crashes during blind flying is due to the tailspin. This conclusionis based, in part, upon observations of many airminded. persons testedwith mypatented training device, reports of pilots making long distanceflights, and reports of the 'few pilots who have survived such crashes.From carefully conducted experiments in plotting the course of a blindflyer, it has been found, without exception, that no subject pilotmaintained a straight and level course for any appreciable length oftime but soon banked the airplane into a spiral course terminating in adiving spiral. By means of my patented apparatus hereinabove identified,and

also in my application flied July 18, 1961, Serial No. 551,606, entitledMethod of blind flight instructions of which this application is adivision, it has been demonstrated that after a spin the usualinformation from the senses regarding attitude and motion is false andthat a pilot can never trust his sensations unless he has an horizon bywhich to check them. If a pilot, flying in el grm-aneuvers into a spinand then comes out, he has the sensation of spinning in the oppositedirection. If he correctsfor the supposed spin, this correction" putshim in another spin and this may continuein a vicious circle until hecrashes. His only hope, therefore, is to disregard his sensations andfly by his instruments.

The failure to make proper use of the instruments is due, principally,to a lack of confidence in flying instruments, ignorance of the factthat they furnish an artificial horizon. for the visual reference andguidance of the pilot in fog, and ignorance of the fact that the pilotssense of fact. To follow ones instrument, even after a demonstration asto the absolute unreliability (under certain conditions) of his ownsense of direction and movement is difficult withouhspecial training,because these erroneous sensations the pilot'receives are overpoweringuntil hehas been trained to disregard them. In this connection, it isinteresting to note that trained flyers were found to be unable toblind-fly a course by instruments without re-education even though theyrealized its necessity. They had been flying too long by feel to be ablesuddenly to disregard their sensations. On the other hand, untrained orvery slightly trained flyers are found to do fairly well because ofhaving nothing to unlearn:

Following preliminary training, after the pilot is convinced of thenecessity for complete reliance on his instruments when in fog orclouds, the training is carried on in an airplane under conditionssimulating those of fog or clouds. This flight training is carried outin a training plane either of the open cockpit type or the cabin type.The former is shown in Figure 1 and embodies tandem cockpits i and 2,the forward one of which is occupied by the student-pilot while theother i occupied by the instructor pilot. A detachable hood 3 covers theforward cockpit and completely encloses the student pilot so that he hasno outside visual reference and is compelled to rely, for flightpurposes, either upon the artificial horizon provided by his flightinstruments or upon his own sensations. In the cabin plane, Fig. 2, thestudent pilot is completely enclosed windows as at 5, to prevent anyvision out and a partition 6 separates the student pilot in the blindedcompartment from the safety pilot in the rear compartment 1.

The relative arrangement ofthe cockpit and compartment is not essentialand the student compartment may, if desired, be behind the safety pilotseat. In either case, the training plane is equipped with duplicate setsof flight instruments, one for each pilot, dual controls and telephonicmeans of communication between the pilots. Each instrument set includesamong others, as shown in Fig. 3, the usual air speed indicator 8,turn-and-bank indicator 9, and altimeter i0. The safety pilot handlesthe controls when taking off and landing the airplane, but turns thecontrols over to the student pilot at a safe altitude. The "blind pilotis then instructed to take control of the plane and after doing soinvariably directs it along the course graphically shown in Fig. 4. Thiscourse will involve at least two (as shown in Fig. 4), and never morethan ten continuous circles within a time interval of one to two minutesbefore the pilot is disoriented with respect to the surface'of the earthand it is necessary for the instructing pilot to take over control ofthe plane. Just prior to taking over control of the plane theinstructing pilot restores outside vision to the student pilot so thatthe latter by observing the dangerous position into feel or balance maybe interpreted contrary to which the airplane has been maneuvered willbe forceably impressed with the necessity of disregarding normalreactions and of following instrumentreadings. A number of hours aregiven over to practice flights, with the safety pilottouchingthe-controls only when necessary to bring the airplane backinto. control, until the student has become accustomed to fly byinstrumerits as against. instinct and is able to take-off, fLv,maneuver, and land without outside visual reference or in other wordsuntil the reflex actions of the student pilothave been properly changed.

The spiral course taken by a pilot depending on his senses rather thanon his instruments the right. When the airplane gets in a' position .inthe forward compartment 4 by covering the as shown at B, the pilot willhave his plane banked 30 to 40 degrees although he'will feel that he isflying straight and level, .He will not have any knowledge of his rightwing being down or of the fact that he is circling to the right; On thecontrary, he will feel that he is flying straight and in many casesthink he is turning to the left. A glance at his instruments will showhim the true position of his plane. However, flying by his own sense offeel or balance, he will correct for a slight left turn, with the resultthat he puts his plane in a still steeper bank to the right. The speedof ,the plane increases as the nose drops, as indicated at position Cand the natural action of the pilot is to move the stick back to checkthe increasing speed. The

plane being at this time in practically a vertical bank. the result ofthis maneuver is a very steep right hand power spiral, as indicated at Dand E. The inevitable result of this is a tail spin, at an air speed of140 M. P. H. or more, as at F. Numerous tests have demonstrated that inthe absence of blind flight training, and regardless of previous flyingexperience, a pilot when given control of a plane will invariably followa right or left hand course similar to that described in the precedingparagraph and shown in Fig. 4. Due to the course taken by the plane, itsinclination laterally and longitudinally with respect to the earthssurface and itsv flying speed, the pilot will become entirelydisoriented relative to the surface of the earth and to the direction offlight; that is to say,'the pilot will be under the impression that theearth rather than the plane is banked and thatthe plane is turning in adirection opposite to' its actual direction of flight. In other wordsassuming the course of the plane to be that shown in Fig. 4, althoughthe plane is rapidly approaching a vertical bank preliminary to a spinand is turning to the right the pilot will be under the impression thatthe plane is on a level keel and is turning to the left. Investigationof this'phenomena and an analysis of the course, invariably taken by theuntrained pilot upon assuming control of a plane, led to the discoveryupon whichthe instant invention is based, namely that subjecting thepilot to a course involving at least two continuous circles with theplane banked within the banking range of 30 to 40 and traveling at aspeed of at least 7. miles an'hour will develop erroneous sense reasaamoactions which if acted upon will, to say the least, jeopardize both theplane and its pilot.

The reaction is very much the same as if they did not have theinstruments. Until pilots have been instructed in their use and trainedto ignore their own reflexes, blind flying will always be a dangerouspractice. The conflict between the pilot's own sensations and theindications of the instruments is illustrated in Fig. 5. When thepilot's senses, for example, indicate the attitude .of the plane asbeing a left bank-nose down. the

actual attitude as indicated by the instruments will be a rightbankenose down. A little time in the air in a covered cockpit willdemonstrate this and the proper training will enable the pilot todisregard his erroneous sensations.

The preliminary training in the revolving. chair is not essential,though it may be desirable, and the candidate's training may beinitially carried on in a training plane with the hooded cockpit.

It has been found, by experience, that a pilot trained to fly in thismanner may be less apprehensive when caught in bad weather than oneinstructed in the normal flight training, since his flrst experiences inthe air have been in the hooded cockpit and hence, without outsidevisual reference.

Experiments prove that if the pilot is thoroughly. familiar with thereason as to why he must fly by his instruments in fog, and then islater trained, as herein described, to fly by instrument, he will notrevert to flying by instinct or sense of feel if the hood or cover oithe cockpit is opened while the airplane is flying in fog.

Having described my" invention, what I claim um and wish to secure byLetters Patent is:

1. Process useful in blind flight training-comprising subjecting aperson to the effect of all the factors, including that ofnon-visibility, normally associated with flying in an airplane in a fogwithout flying instruments and maintaining said factors under control,to thereby produce in the person a predetermined mental state of falseconviction as to the position and direction of movement of the planerelatively to the ground which governs his reflex actions with respectto the airplane controls, and then at a predetermined time subjectingthe person to the effect of the factor of visibility of the ground tothereby change said mental state of the person to a state of trueappreciation of the position and direction of movement of the planerelatively to the ground and also change his reflex actions as to theairplane controls,

2. Process useful in blind flight training comprising subiecting aperson to the effect of all the factors, including that ofnon-visibility, nor-' mally associated with flying in an airplane in afog without flying instruments and maintaining said factors undercontrol, to thereby produce in the person a predetermined mental stateof ialse conviction as to the position and direction of movement of theplane relatively to the ground which governs his reflex actions withrespect to

